The present invention relates to an ozone generator of stack-type design, employing round plate-shaped high-voltage electrodes which are braced counter to one another, two plates, made of an insulating material, being located between two solid electrodes which are spaced one from the other, and a counter-electrode being located between the plates which are made of an insulating material, thereby forming two discharge spaces with the plates, the outer diameter of this counter-electrode being smaller than that of the plates which are made of an insulating material and which clamp a ring, running near their edges, in a manner whereby the ring is squeezed between them.
An ozone generator of this generic type is known from German Auslegeschrift [Published Application] No. 1,176,100. Aluminum spacer rings are inserted between the solid aluminum electrodes, which are water-cooled at their outer edges, these spacer rings possessing shoulders which engage behind axial, dish-like projections on the solid electrodes. There then follow two plates, made of an insulating material, namely glass, which are separated from the electrodes by means of sealing washers. These glass plates are spaced, one from the other, by means of a ring which is made of a non-conducting, ozone-resistant material, this ring receiving the counter-electrode at its edge, and supporting it. The stack is held together, at the outer edge, by means of clamping bolts.
However, the above-mentioned ring between the glass plates has no influence on the dielectric strength of the radial insulating section between the counter-electrode and the metal spacer ring, since the sealing washers, inserted between the solid electrodes and the glass plates, prevent the generation of a significant surface pressure between the glass plates and the ring during the process of tightening the clamping bolts. For this reason, the aluminum spacer rings must be designed with an inner diameter, in relation to the outer diameter of the counter-electrodes, equal to that which they would have if the rings made of a non-conducting material were absent. In consquence, for a given external diameter of the assembly, the restricted diameter of the discharge space results in its active area being very small.
In the case of another ozone generator, according to German Pat. No. 2,412,770, there is no corresponding ring between the glass plates. In this generator, the counter-electrodes are held between the glass plates by means of small separators, and the process gas flows over the edges of the counter-electrodes. Here, too, the active area of the discharge space is correspondingly small.